Fine Structures of the Inner Solar Corona and the Associated Magnetic Topology

Abstract

We present the fine structure of the inner solar corona between 1.65 and 3.0 solar radii as revealed by the STEREO-A COR1 white-light coronagraph from 2008 June 20 to July 31. The COR1 imaging data were wavelet processed to enhance the intensity contrast of coronal features. The constructed limb synoptic maps at a range of altitudes show the evolution in time and altitude of these fine structures within the streamer belt, and equatorial and polar coronal holes during this period near the solar minimum. Distinct streamer-stalk structures are seen embedded within a diffuse background of the helmet streamer belt, which are preserved as they extend to higher heights. Pseudostreamers are also seen as multiple stalk structures, which also continue to higher heights. Various polar plume structures are seen to last from hours to days. Similar plume structures are also seen within the corona subtended by equatorial coronal holes. We compare the COR1 maps to that of the magnetic topology revealed by the modeled squashing factors, and discuss the relation between the two types of maps and its implications in the context of solar wind formation.